Writing music (Anti-Necroposting addition!)

What I want to be able to do is stick as many themes as possible into my work coherently, the intro is basically the same two chords played over for 40 seconds in this (I'm not going to scrap it, but I feel like I need to move on quicker). Each time I make something it ends up being all adding/removing layers, which is fine but I want to extend my ability to multiple styles.